Data logger



FIG. 1 is a right front perspective view of a data logger showing our new design;

FIG. 2 is a left rear perspective view thereof;

FIG. 3 is a right side elevational view thereof;

FIG. 4 is a left side elevational view thereof;

FIG. 5 is a top plan view thereof;

FIG. 6 is a bottom plan view thereof; 

The ornamental design for a data logger, substantially as shown and described. 